In a high-voltage and high-power power electronic converter, series connection technology for Insulated Gate Bipolar Transistor (IGBT) is usually used to effectively increase a voltage level so as to meet needs of relatively high voltage applications. Series connected IGBTs may have uneven voltages and high voltage spikes, and it is usually necessary to add an active clamp circuit between the collector and the gate of each IGBT to solve the problem of uneven voltages and high voltage spikes.
At present, in an active clamp circuit for an IGBT, usually a voltage regulator diode connecting in series with other circuits is connected inversely between the collector and the gate of the IGBT, or between the collector and the driver circuit of the gate. When a voltage of the collector exceeds a preset voltage value, the voltage regulator diode breaks down inversely, and charges are injected into the gate or the driver circuit of the gate, such that a voltage Vge of the gate of the IGBT rises, and an impedance between the collector and an emitter decreases. Thus, the charges can be discharged so as to reduce the voltage Vce between the collector and the emitter, and prevent overvoltage of the IGBT. Since the energy of the overvoltage of the IGBT is released by the IGBT itself, the loss of IGBT may be increased.
Therefore, there is a need for a new active clamp circuit for a power semiconductor switch.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.